The present invention relates to a process or method for producing cutter body members for solid waste material shredding and comminuting apparatus. Such comminution is commonly performed by feeding solid waste materials into the interface of counter-rotating intermeshing cutters. Shrearing and cutting action may occur when particles of waste material are cut or crushed by such intermeshing cutters.
In the prior art of such comminuting devices there is provided at least a pair of rotating shafts with their axes of rotation parallel to one another, with sets or stacks of individual cutter disks and spacers in alternate spaced apart relationship fixedly mounted on each shaft and mutually intermeshing. The spacers are maintained at a fixed separation distance between the teeth of the cutter disks. When such apparatus is operated over an extended period of time or required to comminute bulky solid waste materials, the individual cutter disks and/or the shredding teeth thereof may become dislodged, distorted, broken-off or slip in rotation along along the axis of the shafts owing to the fact that such cutter disks and teeth are subjected to large shrear, shock, bending and torsion forces which must be borne or carried solely by an individual disk or tooth. Stated differently, there is no opportunity for the sharing or distribution of such forces among the various adjacent disks, teeth or spacers along the axis of a shaft. Consequently, such prior art devices are subject to many undesireable drawbacks and disadvantages, which may be observed as for example in the accummulation of waste materials between the cutter members, failure of one or more of the cutter disks to rotate, misalignment of the cutter teeth, anyone or all of these causes reduced comminution efficiency and reliability and the like.
Apparatus of the type to which the present invention relates, are known and described in the prior art, for example, such as U.S. Pat. No. 4,046,324, to Joseph W. Chambers, issued Sep. 6, 1977, entitled "SOLID WASTE COMMINUTION". This device has two interacting stacks of shredding members mounted on substantially parallel shafts and are positioned in transverse arrangement with respect to the direction of the waste material is introduced into the comminutor apparatus. A shredding disk of each stack interacts with a shredding member on the other stack, whereby the individual cutter members cooperately interact in pair within the comminutor. Teeth are provided on at least one member of each pair of shredding members for cutting during rotation thereof. The primary novlty of this prior art apparatus appears to to reside in the existence of cutter disks having shredding members or teeth for cutting in both directions of shaft rotation and the ability of the shafts to be driven in either direction, whereby the device cuts in both directions.
In another U.S. Pat. No. 4,690,340, to Takefumi Hatanaka, issued Sep. 1, 1987, entitled "Waste Material Shredder", there is disclosed an apparatus having a pair of counter-rotating cutter rollers with mutually meshing individual cutter disks mounted thereon and fixed individual spacer members separating the cutter disks. This device is directed toward eliminating jamming of the shredder due to the buildup of chips during the shredding of sheets of waste material between the spacers. Jamming of the device is said to be eliminated by a special configuration of the cutter disks, with chip clearance protrusions being formed between the peripheral teeth which act to remove such chips, thereby overcomming a problem with prior art "cross-cut" type shredders.
In yet another U.S. Pat. No. 4,565,330, to Hiroharm Katoh, issued Jan. 21, 1986, entitled "Shredding Apparatus", and U.S. Pat. No. 4,757,949, to Norman P. Horton, issued Jul. 19, 1988, entitled "Apparatus for Shredding Rubber Tires", each also discloses cutter disks with separating spacer disks disposed on substantially parallel twin shafts which are rotatable in opposing directions in intermeshing relationship.
In still another U.S. Pat. No. 3,860,180, to Albert Goldhammer, issued Jan. 14, 1975, entitled "Method and Apparatus for Destroying Documents", there is disclosed a method and apparatus for destroying documents in which opposed slitter rollers are provided that slit a document into longitudinal strips while the rollers are provided with means for cutting each longitudinal piece into a plurality of short sections.
Finally, in U.S. Pat. No. 3,633,831, to Marshall A. Dodson et al, issued Jan. 11, 1972, Entitled "Granular Device and Helical-Shaped Cutters Therefore ", there is disclosed a pair of meshing cutters used in a granular device having a pair of helical continuous tooth members such as one piece gears, which have each had their tooth shapes modified so as to exert a continuous scissors-type shear cutting action on material fed to them as a continuous web or as individual pieces or a combination thereof.
It should be noted that each of the above cited patented apparatus and other prior art patents not cited utilize as a necessity and novelty thereof, the individual cutter and spacer disk arrangements for their operaration and provision of such comminutor devices. Various protruding teeth configurations, multiple teeth on the cutter disks, differences in root diameters of the cutter teeth and spacers and the like are utilized to accommodate a variety of waste materials to enhance the utility of such prior art devices. However, none of the known prior art devices solves the long standing and continued problems of poor efficiency for shredding, sizing, jamming, distortion, broken teeth or dislodgement of cutter disks or teeth when such arrangements are utilized. Thus, it appears that the most commonly used techinues in the prior art are to use alternate stacking of cutter and spacer disks on shafts to provide an arrangement for the shredder inter-meshing or inter-action, and therefore, have either not realized or appreciated the need to provide a cutter body arrangement which is strong and durable, and which is capable of effectively distributing the stresses encounted therein along the axial length of the apparatus rather than having it concentrated on individual cutter and disk members as heretofore experienced.